1. Field of the Invention
The present invention relates to a system and method for evaluating communication quality of a mobile terminal in a mobile communication network.
2. Description of the Related Art
In the field of a mobile communication network, generally, a high-performance mobile terminal called a smart phone or a personal computer (PC) accesses the Internet via such a high-speed broadband network as a high-speed broadband mobile communication, e.g., a high speed packet access (HSPA) or evaluation-data optimized (EV-DO) as a 3rd generation (3G) high-speed data communication service and worldwide interoperability for microwave access (WiMAX) or long-term evolution (LTE) as a 3.9G high-speed data communication service. As a mobile communication network becomes widely spread, demands for high communication quality increase, so that a mobile communication service provider is requested to monitor communication quality and improve a poor quality area. Since the number of base stations also increases in order to handle an increasing traffic amount, it is necessary to efficiently check communication quality in each base station.
Presently, for communication quality management in a mobile communication network, a check is performed by estimating a congestion state and thus communication quality is based on a link occupation rate. However, it has been difficult to accurately check communication quality because a relationship between the link occupation rate and the quality such as a file transfer time or a throughput actually sensed by a user is not known.
For directly checking the communication quality, there is known an active measurement technique in which information such as a communication delay, a packet loss, and a throughput is obtained by actively transmitting and/or receiving a test packet. However, in such a technique, it is necessary to transmit and/or receive the test packet by installing a test packet transceiver in both entrance and exit sides of a monitoring target network, so that a measurement unit cost increases. In addition, since extra traffic is added to a network due to the test traffic in order to transmit the test packet to a network, there is a problem that network quality itself is degraded.
As one technique other than active measurement, there is known a passive measurement technique in which a network condition is checked by capturing and analyzing a packet passing through a portion where end-to-end traffic to be looked at flows.
For example, a communication quality measurement method is described in JP 2011-124750 A, which discloses a method for estimating network communication quality by measuring a round-trip time (RTT) using a SYN packet and a SYN+ACK or ACK packet.